Mumps outbreaks, especially in adolescents and young adults, have been reported in the Czech Republic. The aim of the presented study was to determine the seroprevalence of specific IgG antibodies against mumps in the adult population of the Czech Republic. The study was designed as a multicenter serological survey of adults aged 18 years and over. Specific IgG antibodies against mumps were detected in blood samples using an enzyme-linked immunosorbent assay (ELISA). A total of 1,911 serum samples were examined. The overall seropositivity reached 55.3%. In individual age groups, the highest seropositivity 63% (63.5-65.2%) was recorded in adults aged 40 years and over; the lowest seropositivity was found in adults aged 18-29 years (27.4%). The difference in seropositivity rate between the 18-29 years age group and the 40 years and over age groups was statistically significant (p < 0.001). Only the 18-29 years age group included both vaccinated and unvaccinated (born in the pre-vaccine era) individuals. In vaccinated individuals, seropositivity was reported in only 19.1% of persons; in unvaccinated individuals, seropositivity reached 48.2%. Our results demonstrate the long-term persistence of antibodies following natural infection and the decrease in seropositivity that occurs after vaccination over time. This immunity waning may account for the higher susceptibility of adolescents and young adults to mumps. Therefore, the current vaccination program in the Czech Republic could be considered as less effective. It will be modified with the shifting of the second dose of vaccine from two years of age to the preschool age.

• Klíčová slova
• Czech Republic, adults, antibodies, mumps, seroprevalence, vaccination program,
• MeSH
• dospělí MeSH
• epidemický výskyt choroby prevence a kontrola   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• očkovací programy metody   MeSH
• příušnice krev   imunologie   prevence a kontrola   MeSH
• protilátky virové krev   imunologie   MeSH
• průzkumy a dotazníky MeSH
• senioři MeSH
• séroepidemiologické studie MeSH
• spalničky imunologie   prevence a kontrola   MeSH
• vakcína proti spalničkám, příušnicím a zarděnkám imunologie   MeSH
• vakcinace metody   MeSH
• virus příušnic imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• protilátky virové MeSH
• vakcína proti spalničkám, příušnicím a zarděnkám MeSH

BACKGROUND: In the Czech Republic, two-dose immunization against mumps achieves 98% coverage. The routine reporting detects mumps cases, clinical complications, and hospital admissions in unvaccinated but also in vaccinated individuals. Using surveillance data of patients with mumps we assessed the effectiveness of mumps vaccination on mumps clinical complications and hospitalization need. We also investigated the effect of the time since immunization. METHODS: We analysed data on incident mumps cases reported to the Czech national surveillance system in 2007-2012. Using a logistic regression model with adjustment for age, sex, year of onset, and the administrative region, the association between vaccination and the most frequent mumps complications and hospitalization was evaluated. The adjusted odds ratios (ORa) for mumps complications were compared between the vaccinated and non-vaccinated groups, reflecting the vaccine effectiveness (VEa) computed as VEa = (1-ORa) × 100. We estimated the risk of mumps complications by the time from vaccination. RESULTS: From total of 9663 mumps analysed cases 5600 (58%) occurred in males. The mean age at the disease onset was 17.3, median 16 years. Ninety percent of the study patients had no complications, while 1.6% developed meningitis, 0.2% encephalitis, and 0.6% pancreatitis. Mumps orchitis occurred in 659 (11.8%) male cases. In total, 1192 (12.3%) patients required hospitalization. Two doses of vaccine received by 81.8% cases significantly reduced the risk of hospitalization: ORa 0.29 (95% CI: 0.24, 0.35). Two doses showed statistically significant VEa 64% (95% CI: 46, 79) for meningitis, 93% (95% CI: 66, 98) for encephalitis in all cases, and 72% (95% CI: 64, 78) for orchitis in males. Vaccine effectiveness for orchitis declined from 81 to 74% and 56% in the most affected age groups 10-14, 15-19, and 20-24 years, respectively. Among 7850 two-dose recipients, the rate of complications rose from below 1 to 16% in categories up to 6 years and 24 and more years after the second dose, respectively. CONCLUSIONS: This study demonstrates a significant preventive effect of two-dose vaccination against mumps complications (orchitis, meningitis, or encephalitis) and hospitalization for mumps. The risk of complications increases with time interval from vaccination. Teenagers and young adults were the most affected age groups.

• Klíčová slova
• Hospitalization, Mumps, Mumps complications, Orchitis, Surveillance, Vaccination,
• MeSH
• časové faktory MeSH
• dítě MeSH
• dospělí MeSH
• encefalitida epidemiologie   prevence a kontrola   MeSH
• hospitalizace statistika a číselné údaje   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• meningitida epidemiologie   prevence a kontrola   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• očkovací schéma MeSH
• orchitida epidemiologie   prevence a kontrola   MeSH
• předškolní dítě MeSH
• příušnice komplikace   epidemiologie   prevence a kontrola   MeSH
• riziko MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• surveillance populace * MeSH
• vakcína proti příušnicím aplikace a dávkování   MeSH
• vakcinace statistika a číselné údaje   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• vakcína proti příušnicím MeSH